Heat Pump

ABSTRACT

An outdoor unit of the heat pump includes a compressor, an oil separator provided in a discharge path of the compressor, an outdoor-unit connecting pipe connecting an intake path of the compressor and an outdoor unit of an another heat pump for supplying a refrigerant to the outdoor unit of the another heat pump, an oil supply pipe extending from a predetermined position of the oil separator and connecting to the outdoor-unit connecting pipe, an on-off valve provided on the oil supply pipe, an expansion valve provided in a portion of the outdoor-unit connecting pipe between a connecting part connected to the intake path and a connecting part connected to the oil supply pipe, and a refrigerant filling port provided in a portion of the outdoor-unit connecting pipe between the connecting part and the expansion valve.

TECHNICAL FIELD

The present invention relates to a heat pump.

BACKGROUND ART

Conventionally known heat pumps include a heat pump having an outdoorunit and an indoor unit configured such that when the heat pump is usedas one of a plurality of heat pumps, respective outdoor units of theheat pumps can exchange a refrigerant with indoor units of the pluralityof heat pumps (see, e.g., Patent Document 1). In the case of PatentDocument 1, outdoor units of a plurality of heat pumps are connected toeach other through a connection path, and an on-off valve is provided inthe connection path. A refrigerant is exchanged also between the outdoorunits through this connecting path and the on-off valve.

PRIOR ART DOCUMENT Patent Document

Patent Document 1: Japanese Patent No. 4764850

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

Patent Document 1 does not disclose a refrigerant filling port forfilling each heat pump with a refrigerant after a plurality of heatpumps is disposed, for example.

Therefore, a problem to be solved by the present invention is to providea heat pump having an outdoor unit and an indoor unit configured suchthat when the heat pump is used as one of a plurality of heat pumps,respective outdoor units of the heat pumps can exchange a refrigerantwith indoor units of a plurality of heat pumps, and including arefrigerant filling port.

Means for Solving Problem

To solve the technical problem described above, an aspect of the presentinvention provides

-   -   a heat pump having an outdoor unit,    -   the outdoor unit including    -   a compressor,    -   an oil separator provided in a discharge path of the compressor,    -   an outdoor-unit connecting pipe connecting an intake path of the        compressor and an outdoor unit of an another heat pump for        supplying a refrigerant to the outdoor unit of the another heat        pump,    -   an oil supply pipe extending from a predetermined position of        the oil separator and connecting to the outdoor-unit connecting        pipe,    -   an on-off valve provided on the oil supply pipe,    -   an expansion valve provided in a portion of the outdoor-unit        connecting pipe between a connecting part connected to the        intake path and a connecting part connected to the oil supply        pipe, and    -   a refrigerant filling port provided in a portion of the        outdoor-unit connecting pipe between the connecting part        connected to the oil supply pipe and the expansion valve.

Another aspect of the present invention provides

-   -   a heat pump having an outdoor unit,    -   the outdoor unit including    -   a compressor,    -   an oil separator provided in a discharge path of the compressor,    -   a refrigerant filling pipe connecting an intake path of the        compressor and an outdoor unit of an another heat pump for        filling the intake path of the compressor with a refrigerant        supplied from the outdoor unit of the another heat pump,    -   an oil supply pipe extending from a predetermined position of        the oil separator and connecting to the refrigerant filling        pipe,    -   an on-off valve provided on the oil supply pipe,    -   an expansion valve provided in a portion of the refrigerant        filling pipe between a connecting part connected to the intake        path and a connecting part connected to the oil supply pipe, and    -   a refrigerant filling port provided in a portion of the        refrigerant filling pipe between the connecting part connected        to the oil supply pipe and the expansion valve.

Effect of the Invention

The present invention can provide the heat pump having an outdoor unitand an indoor unit configured such that when the heat pump is used asone of a plurality of heat pumps, respective outdoor units of the heatpumps can exchange a refrigerant with indoor units of a plurality ofheat pumps, and including the refrigerant filling port.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a circuit diagram of a configuration of a heat pump accordingto an embodiment of the present invention.

FIG. 2 is a perspective view of a portion of the heat pump according tothe embodiment of the present invention.

MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will now be described withreference to the drawings.

FIG. 1 is a circuit diagram of a configuration of a heat pump accordingto an embodiment of the present invention. FIG. 2 is a perspective viewof a portion of the heat pump. In the circuit diagram shown in FIG. 1,for simplification of description, constituent elements such as a filterof the heat pump are not shown.

FIG. 1 shows a plurality of heat pumps, or specifically, two heat pumps10A, 10B each having one outdoor unit 12A, 12B exchanging heat withoutside air and two indoor units 14A, 14B exchanging heat with indoorair.

The respective outdoor units 12A, 12B of the heat pumps 10A, 10B areconfigured to exchange a refrigerant with the indoor units 14A, 14B ofthe plurality of the heat pumps 10A, 10B as described later in detail.

The plurality of the outdoor units 12A, 12B has substantially the sameconfiguration, and the plurality of the indoor units 14A, 14B hassubstantially the same configuration. Therefore, in FIG. 1, the outdoorunit 12B is simplified.

The outdoor units 12A, 12B of the heat pumps 10A, 10B each havecompressors 16 compressing and discharging a refrigerant, heatexchangers 18 exchanging heat with outside air, and a four-way valve 20.On the other hand, the indoor units 14A, 14B each have a heat exchanger22 exchanging heat with indoor air.

The compressors 16 are driven by a drive source 24 such as a gas engine,for example. In the present embodiment, the two compressors 16 and theone gas engine 24 are mounted on each of the outdoor units 12A, 12B. Asshown in FIG. 2, the compressors 16 are both connected via respectiveclutches 26 and a belt 28 to a flywheel 30 attached to an output shaftof the gas engine 24. Because of being connected via the clutches 26, atleast one of the compressors 16 can selectively be driven by the one gasengine 24.

A high-temperature high-pressure gaseous refrigerant discharged fromdischarge ports 16 a of the compressors 16 is directed by the four-wayvalve 20 to the heat exchangers 18 of the outdoor units 12A, 12B or theheat exchangers 22 of the indoor units 14A, 14B. In the case of aheating operation, the gaseous refrigerant discharged from thecompressors 16 is sent to the heat exchangers 22 of the indoor units14A, 14B. On the other hand, in the case of a cooling operation, thegaseous refrigerant is sent to the heat exchangers 18 of the outdoorunits 12A, 12B.

On a discharge path of the compressors 16, i.e., on a refrigerant pathbetween the discharge ports 16 a of the compressors 16 and the four-wayvalve 20, an oil separator 32 separating a refrigerating machine oil(oil) contained in the refrigerant is provided. It is noted that the oilseparated from the refrigerant and stored in a bottom portion 32 a ofthe oil separator 32 is returned through an oil returning path (notshown) to sliding parts in the compressors 16.

In the case of the heating operation, the high-temperature high-pressuregaseous refrigerant discharged from the compressors 16 and passingthrough the four-way valve 20 (solid line) exchanges heat with indoorair in the heat exchangers 22 of the indoor units 14A, 14B. Therefore,heat is transferred from the refrigerant to the indoor air via the heatexchangers 22. As a result, the refrigerant is put into alow-temperature high-pressure liquid state.

A receiver 36 is provided in each of the outdoor units 12A, 12B. Thereceiver 36 is a buffer tank temporarily storing the low-temperaturehigh-pressure liquid refrigerant after the heat exchange with indoor airin the heat exchangers 22 of the indoor units 14A, 14B. The liquidrefrigerant flowing out from the heat exchangers 22 of the indoor units14A, 14B passes through a check valve 34 and flows into the receiver 36.

The low-temperature high-pressure liquid refrigerant in the receiver 36is sent to the heat exchangers 18 of the outdoor units 12A, 12B. A checkvalve 38 and expansion valves 40 are provided in a path between a bottomportion 36 a of the receiver 36 and the heat exchangers 18. Thelow-temperature high-pressure liquid refrigerant flowing out from thebottom portion 36 a of the receiver 36 is expanded by the expansionvalves 40 and put into a low-temperature low-pressure liquid state(atomized state).

The low-temperature low-pressure liquid refrigerant passing through theexpansion valves 40 exchanges heat with outside air in the heatexchangers 18 of the outdoor units 12A, 12B. Therefore, heat istransferred from the outside air to the refrigerant via the heatexchangers 18. As a result, the refrigerant is put into alow-temperature low-pressure gas state.

The outdoor units 12A, 12B are provided with accumulators 42 temporarilystoring the low-temperature low-pressure gaseous refrigerant after theheat exchange with outside air in the heat exchangers 18 of the outdoorunits 12A, 12B. The accumulators 42 are each disposed in an intake pathof the compressors 16 (the path between intake ports 16 b of thecompressors 16 and the four-way valve 20).

The low-temperature low-pressure gaseous refrigerant in the accumulator42 is sucked and compressed in the compressors 16. As a result, therefrigerant is put into a high-temperature high-pressure gas state andis sent toward the heat exchangers 22 of the indoor units 14A, 14Bagain.

While the low-temperature low-pressure gaseous refrigerant temporarilystays in the accumulator 42, a small amount of liquid refrigerantcontained in the gaseous refrigerant is separated. This liquidrefrigerant is stored in the accumulator 42.

On the other hand, in the case of the cooling operation, thehigh-temperature high-pressure gaseous refrigerant discharged from thedischarge ports 16 a of the compressors 16 moves through the four-wayvalve 20 (dashed-two dotted line) to the heat exchangers 18 of theoutdoor units 12A, 12B. By exchanging heat with outside air in the heatexchangers 18, the refrigerant is put into a low-temperaturehigh-pressure liquid state. The refrigerant flowing out from the heatexchangers 18 passes through the expansion valves 40 and is thereby putinto a low-temperature low-pressure liquid state (atomized state). Therefrigerant passing through the expansion valves 40 passes through acheck valve 44, the receiver 36, and a check valve 46 in order andreaches the heat exchangers 22 of the indoor units 14A, 14B. Byexchanging heat with indoor air in the heat exchanger 22, therefrigerant is put into a low-temperature low-pressure gas state. Therefrigerant flowing out from the heat exchangers 22 passes through thefour-way valve 20 and the accumulator 42 and returns to the compressors16.

To improve a cooling efficiency, the outdoor units 12A, 12B of the heatpumps 10A, 10B each have a cooling heat exchanger 48 for cooling therefrigerant from the receiver 36 to the check valve 46.

The cooling heat exchanger 48 is configured such that heat is exchangedbetween the liquid refrigerant from the receiver 36 to the check valve46 and an atomized refrigerant, i.e., such that the liquid refrigerantis cooled by the atomized refrigerant. This atomized refrigerant isacquired by atomizing a portion of the liquid refrigerant from thecooling heat exchanger 48 to the check valve 46 by an expansion valve50. The expansion valve 50 is a valve with an adjustable opening degreefor allowing the cooling heat exchanger 48 to selectively cool theliquid refrigerant.

When a control device (not shown) of the heat pumps 10A, 10B controlsthe expansion valve 50 to at least partially open the expansion valve50, a portion of the liquid refrigerant passing through the cooling heatexchanger 48 before passing through the check valve 46 passes through,and is atomized by, the expansion valve 50. The refrigerant atomized bythe expansion valve 50 flows into the cooling heat exchanger 48, drawsheat from the liquid refrigerant flowing out from the receiver 36 beforepassing through the check valve 46, and thereby gasifies. As a result, aliquid refrigerant at a lower temperature flows into the heat exchangers22 of the indoor units 14A, 14B as compared to when the expansion valve50 is in the closed state.

On the other hand, the gaseous refrigerant drawing the heat from theliquid refrigerant flowing out from the receiver 36 before passingthrough the check valve 46 is directly returned from the cooling heatexchanger 48 to the compressors 16. This gaseous refrigerant is alsoused for evaporating the liquid refrigerant stored in the accumulator42. In particular, when the on-off valve 52 is opened, the liquidrefrigerant in the accumulator 42 is mixed and gasified with the gaseousrefrigerant returning from the cooling heat exchanger 48 to thecompressor 16 and is returned to the compressor 16.

The heat pumps 10A, 10B each have an assist-evaporation heat exchanger54 for gasifying a liquid refrigerant contained in the gaseousrefrigerant returning from the four-way valve 20 to the compressor 16.

To determine whether the liquid refrigerant is contained in the gaseousrefrigerant returning to the compressor 16, a temperature sensor 56 anda pressure sensor 58 for detecting the temperature and the pressure ofthe refrigerant are provided in the path between the four-way valve 20and the accumulator 42. The temperature sensor 56 and the pressuresensor 58 output detection signals corresponding to detection results tothe control device (not shown) of the heat pumps 10A, 10B. Based on thedetection signals from the temperature sensor 56 and the pressure sensor58, the control device determines whether the liquid refrigerant iscontained in the gaseous refrigerant returning to the compressor 16. Inparticular, if the pressure of the refrigerant detected by the pressuresensor 58 is substantially the same as the vapor pressure correspondingto the temperature detected by the temperature sensor 56, it isdetermined that the liquid refrigerant is almost not included in thegaseous refrigerant returning to the compressor 16 (the liquidrefrigerant is substantially zero).

The assist-evaporation heat exchanger 54 utilizes a portion of thelow-temperature high-pressure liquid refrigerant flowing out from thereceiver 36 before passing through the check valve 38. Therefore, anexpansion valve 60 with an adjustable opening degree is provided betweenthe receiver 36 and the assist-evaporation heat exchanger 54.

When determining that a predefined amount or more of the liquidrefrigerant is contained in the gaseous refrigerant returning to thecompressor 16, the control device (not shown) of the heat pumps 10A, 10Bcontrols the expansion valve 60. As a result, the expansion valve 60 isat least partially opened.

When the expansion valve 60 is at least partially opened, a portion ofthe low-temperature high-pressure liquid refrigerant flowing out of thereceiver 36 before passing through the check valve 38 flows through theexpansion valve 60 and is put into a low-temperature low-pressureatomized state.

The atomized refrigerant passing through the expansion valve 60 isheated in the assist-evaporation heat exchanger 54 by high-temperatureexhaust gas or coolant of the gas engine 24, for example. As a result,the atomized refrigerant flowing through the expansion valve 60 into theassist-evaporation heat exchanger 54 is put into a high-temperaturelow-pressure gas state. The high-temperature gaseous refrigerant heatedby the assist-evaporation heat exchanger 54 is put into the path betweenthe four-way valve 20 and the accumulator 42. Therefore, the liquidrefrigerant contained in the gaseous refrigerant returning through thefour-way valve 20 to the compressor 16 is heated and evaporated(gasified) by the high-temperature gaseous refrigerant from theassist-evaporation heat exchanger 54. As a result, the refrigerantflowing into the accumulator 42 is put into a substantially gaseousstate.

Description will be made of heat pump constituent elements utilized whena plurality of heat pumps is used.

First, as shown in FIG. 1, the respective indoor units 14A, 14B of theheat pumps 10A, 10B are connected to common refrigerant pipings 62, 64.The respective outdoor units 12A, 12B of the heat pumps 10A, 10B arealso connected to the common refrigerant pipings 62, 64. As a result, atleast one of the outdoor units 14A of the heat pump 10A and the outdoorunits 14B of the heat pump 10B can exchange the refrigerant with atleast one of the indoor units 14A, 14B through the common refrigerantpipings 62, 64.

For example, both the outdoor units 12A, 12B (the compressors 16thereof) are operated while at least one of the indoor units 14A, 14B isoperated in some cases. Each of the indoor units 14A, 14B is providedwith an expansion valve 66 with an adjustable opening degree. When theexpansion valve 66 is opened, the refrigerant flows into the heatexchanger 22, and each of the indoor units 14A, 14B is operated.Additionally, by adjusting the opening degree of the expansion valve 66,the output of each of the indoor units 14A, 14B is adjusted.

Alternatively, for example, only one of the outdoor units 12A, 12B (thecompressors 16 thereof) is operated while at least one of the indoorunits 14A, 14B is operated in other cases. Specifically, the totaloutput of at least one of the indoor units 14A, 14B may be satisfied bythe output of either one of the outdoor units 12A, 12B. In such a case,either one of the outdoor units 12A, 12B (the compressors 16 thereof) isoperated and the other is stopped. This is because it is better to driveonly one of the gas engines 24 of the outdoor units 12A, 12B at therated output and stop the other, as compared to driving both of the gasengines 24 of the outdoor units 12A, 12B at an output lower than therated output, in terms of fuel consumption, energy efficiency, lifespan, etc.

However, when only one of the outdoor units 12A, 12B (the compressors 16thereof) is operated, the refrigerant may become insufficient in theoperating outdoor unit. This is because the refrigerant flowing out fromthe heat exchangers 22 of the indoor units 14A, 14B tends to flow towardthe stopped outdoor unit rather than the one operating outdoor unit ofthe outdoor units 12A, 12B.

If the refrigerant becomes insufficient in either one of the outdoorunits 12A, 12B, an oil lubricating the compressors 16 of the operatingoutdoor unit may accordingly become insufficient. This is because theoil-containing refrigerant discharged from the compressors 16 of theoperating outdoor unit flows out from the heat exchangers 22 of theindoor units 14A, 14B and then flows together with the oil to thestopped outdoor unit.

To take a countermeasure, the outdoor unit of the heat pump of thepresent embodiment is configured such that when the heat pump is used asone of a plurality of heat pumps, the refrigerant and the oil can besupplied from a stopped outdoor unit to an operating outdoor unit.

Description will be made of the case that the outdoor unit 12B is inoperation while the outdoor unit 12A is stopped by way of example. It isnoted that the following description can be applied by replacing thesuffixes “A” and “B” of reference numerals to the case that the outdoorunit 12A is in operation while the outdoor unit 12B is stopped.

As shown in FIG. 1, when the outdoor unit 12B is (the compressors 16thereof are) in operation, the refrigerant flowing out from the outdoorunit 12B (and the oil contained therein) flows through the commonrefrigerant piping 62 into the heat exchanger 22 of at least one of theindoor units 14A, 14B. Although a large portion of the refrigerant afterheat exchange with indoor air in the heat exchanger 22 flows toward theoutdoor unit 12B due to suction by the compressors 16 of the operatingoutdoor unit 12B, a portion thereof flows toward the stopped outdoorunit 12A. The portion of the refrigerant stays in the stopped outdoorunit 12A. Therefore, a portion of the refrigerant must be supplied fromthe stopped outdoor unit 12A to the operating outdoor unit 12B.

To supply the refrigerant from the stopped outdoor unit 12A to theoperating outdoor unit 12B, the stopped outdoor unit 12A has anoutdoor-unit connecting pipe 70 for connecting to the operating outdoorunit 12B.

The outdoor-unit connecting pipe 70 of the stopped outdoor unit 12Aconnects the intake path of the compressors 16 thereof and the operatingoutdoor unit 12B. In the case of the present embodiment, one end of theoutdoor-unit connecting pipe 70 of the stopped outdoor unit 12A isconnected to a path portion that is a portion of the intake path of thecompressors 16 (a connecting part 70 a) between the assist-evaporationheat exchanger 54 and the expansion valve 60. On the other hand, amanually openable/closable on-off valve 72 is provided in the vicinityof the other end.

As shown in FIG. 2, a connector 74 for connecting to the operatingoutdoor unit 12B is provided at the other end of the outdoor-unitconnecting pipe 70 of the stopped outdoor unit 12A. Specifically, theconnector 74 of the outdoor-unit connecting pipe 70 in the stoppedoutdoor unit 12A is connected through a connecting piping 76 shown inFIG. 1 to the connector 74 of the outdoor-unit connecting pipe 70 in theoperating outdoor unit 12B. As a result, the refrigerant can flow fromthe outdoor-unit connecting pipe 70 in the stopped outdoor unit 12Athrough the connecting piping 76 toward the outdoor-unit connecting pipe70 in the operating outdoor unit 12B. Therefore, in the operatingoutdoor unit 12B, the outdoor-unit connecting pipe 70 functions as arefrigerant filling pipe for filling the intake path of the compressors16 with the refrigerant supplied from the stopped outdoor unit 12A.

In the stopped outdoor unit 12A, a large portion of the refrigerant isstored in the receiver 36 and the heat exchangers 18. For supplying therefrigerant in the receiver 36 of the stopped outdoor unit 12A to theoperating outdoor unit 12B, a first refrigerant supply pipe 78 fordirectly connecting the receiver 36 and the outdoor-unit connecting pipe70 is provided in the outdoor unit 12A.

The first refrigerant supply pipe 78 is connected to a side surface 36 bof the receiver 36. Specifically, the first refrigerant supply pipe 78is connected to a position of the side surface 36 b of the receiver 36located at a predetermined height with respect to the bottom portion 36a. As a result, the refrigerant stored in the receiver 36 of the stoppedoutdoor unit 12A can be supplied through the first refrigerant supplypipe 78 and the outdoor-unit connecting pipe 70 to the operating outdoorunit 12B. A predefined amount of the refrigerant can be left in thereceiver 36 in preparation for a future operation of the stopped outdoorunit 12A.

The first refrigerant supply pipe 78 is provided with an on-off valve 80and a check valve 82. When the outdoor unit 12A is (the compressors 16thereof are) in operation, the on-off valve 80 is in a closed state.When the outdoor unit 12A is stopped, the check valve 82 prevents abackward flow of the refrigerant through the first refrigerant supplypipe 78 to the receiver 36.

A second refrigerant supply pipe 84 is provided in the outdoor unit 12Aso as to supply the refrigerant in the heat exchangers 18 of the stoppedoutdoor unit 12A to the operating outdoor unit 12B.

One end of the second refrigerant supply pipe 84 is connected to thepath between the four-way valve 20 and the heat exchangers 18.Specifically, the path between the four-way valve 20 and the heatexchangers 18 is provided with an on-off valve 86 closed so as toprevent the refrigerant from flowing backward from the heat exchangers18 to the discharge path (the discharge ports 16 a) of the compressors16 while the compressors 16 are stopped. The one end of the secondrefrigerant supply pipe 84 is connected between the on-off valve 86 andthe heat exchangers 18.

On the other hand, the other end of the second refrigerant supply pipe84 is connected to the path between the assist-evaporation heatexchanger 54 and the expansion valve 60.

As a result, the refrigerant stored in the heat exchangers 18 of thestopped outdoor unit 12A can be supplied through the second refrigerantsupply pipe 84 and the outdoor-unit connecting pipe 70 to the operatingoutdoor unit 12B.

The second refrigerant supply pipe 84 is provided with an on-off valve88 and a check valve 90. When the outdoor unit 12A is (the compressors16 thereof are) in operation, the on-off valve 88 is in a closed state.When the outdoor unit 12A is stopped, the check valve 90 prevents abackward flow of the refrigerant through the second refrigerant supplypipe 84 to the heat exchangers 18.

As described above, a portion of the refrigerant in the receiver 36 andthe refrigerant in the heat exchangers 18 of the stopped outdoor unit12A are supplied through the first and second refrigerant supply pipes78, 84 and the outdoor-unit connecting pipe 70 to the operating outdoorunit 12B. However, the refrigerant may still become insufficient in theoperating outdoor unit 12B.

In this case, the refrigerant is further supplied from the receiver 36of the stopped outdoor unit 12A to the operating outdoor unit 12B.

Specifically, in the heating operation, the on-off valve 100 of thestopped outdoor unit 12A is opened to draw the discharged refrigerant ofthe operating outdoor unit 12B to push out the refrigerant staying inthe receiver 36 to the check valve 46 and the first refrigerant supplypipe 78. The refrigerant pushed out to the check valve 46 flows throughthe common refrigerant piping 64 to the operating outdoor unit 12. Therefrigerant pushed out to the first refrigerant supply pipe 78 flows viathe on-off valve 80 and the check valve 82 from the connecting piping 76to the outdoor unit 12B. In this case, the opening degree of theexpansion valve 110 of the outdoor unit 12B is controlled to adjust theamount of refrigerant flowing from the connecting piping 76.

On the other hand, in the cooling operation, the on-off valve 88 of thestopped outdoor unit 12A is opened so that the refrigerant staying inthe heat exchangers 18 is sucked through the check valve 88, the secondrefrigerant supply pipe 84, the assist-evaporation heat exchanger 54,the four-way valve 20, and the common piping 62 to the operating outdoorunit 12B.

The refrigerant is supplied from the outdoor unit 12A to the operatingoutdoor unit 12B through the first and second refrigerant supply pipes78, 84 of the stopped outdoor unit 12A (in some cases, also through thethird and fourth refrigerant supply pipes 92, 98). In addition, the oilfor lubricating the compressors 16 of the operating outdoor unit 12B issupplied from the stopped outdoor unit 12A.

Therefore, an oil supply pipe 104 extending from a predeterminedposition of the oil separator and connecting to the outdoor-unitconnecting pipe 70 is provided in the outdoor unit 12A.

On the other hand, one end of the oil supply pipe 104 is connected to aportion of the outdoor-unit connecting pipe 70 (a connecting part 70 b)between the connecting part 70 a connected to the intake path of thecompressors 16 and the manual on-off valve 72.

On the other hand, the other end of the oil supply pipe 104 is connectedto a predetermined position of the side surface 32 b of the oilseparator 32 located at a predetermined height with respect to thebottom portion 32 a of the oil separator 32. As a result, the oil storedin the oil separator 32 of the stopped outdoor unit 12A can be suppliedthrough the oil supply pipe 104 and the outdoor-unit connecting pipe 70to the operating outdoor unit 12B. A predefined amount of the nil can beleft in the nil separator 32 in preparation for future operation of thestopped outdoor unit 12A (the compressors 16 thereof).

The oil supply pipe 104 of the stopped outdoor unit 12A is provided withan on-off valve 106 and a check valve 108. When the outdoor unit 12A isin operation, the on-off valve 106 is closed. The check valve 108prevents inflow of the refrigerant from the outdoor-unit connecting pipe70 into the oil separator 32.

The operating outdoor unit 12B supplied with the refrigerant and the oilfrom the stopped outdoor unit 12A will hereinafter be described. Theconfigurations of the outdoor units 12A, 12B are substantially the sameas described above. Therefore, for understanding of the configuration ofthe outdoor unit 12B, the configuration of the outdoor unit 12A shown inFIG. 1 can be used.

The refrigerant supplied from the stopped outdoor unit 12A flows intothe outdoor-unit connecting pipe 70 (i.e., the refrigerant filling pipe)of the operating outdoor unit 12B. In the operating indoor unit 12B, theon-off valve 80 on the first refrigerant supply pipe 78, the on-offvalve 88 on the second refrigerant supply pipe 84, the on-off valve 94on the third refrigerant supply pipe 92, the on-off valve 100 on thefourth refrigerant supply pipe 98, and the on-off valve 106 of the oilsupply pipe 104 are closed. Therefore, the refrigerant flowing into theoutdoor-unit connecting pipe 70 of the operating outdoor unit 12B passesthrough the assist-evaporation heat exchanger 54 and the accumulator 42in order and enters the intake ports 16 b of the compressors 16.

The expansion valve 110 with an adjustable opening degree is provided onthe outdoor-unit connecting pipe 70 of the operating outdoor unit 12B.The expansion valve 110 is provided in a portion of the outdoor-unitconnecting pipe 70 between the connecting part 70 a connected to theintake path of the compressors 16 and the connecting part 70 b connectedto the oil supply pipe 104. When the refrigerant is exchanged via theoutdoor-unit connecting pipe 70 between the stopped outdoor unit 12A andthe operating outdoor unit 12B, the expansion valve 110 is opened.

The refrigerant supplied from the stopped outdoor unit 12A and flowinginto the outdoor-unit connecting pipe 70 in the operating outdoor unit12B is atomized by the expansion valve 110. The refrigerant atomized bythe expansion valve 110 is heated and gasified by the assist-evaporationheat exchanger 54. As a result, the refrigerant supplied from thestopped outdoor unit 12A can flow into the compressors 16 of theoperating outdoor unit 12B in the gas state.

The oil supplied from the stopped outdoor unit 12A accompanies therefrigerant supplied from the outdoor unit 12A and flows into theoutdoor-unit connecting pipe 70 (i.e., the refrigerant filling pipe) ofthe operating outdoor unit 12B in the same way. Therefore, theoutdoor-unit connecting pipe 70 (Le., the refrigerant filling pipe)functions as an oil supply path for supplying not only the refrigerantbut also the oil.

The oil flowing into the outdoor-unit connecting pipe 70 of theoperating outdoor unit 12B enters the compressors 16 along with therefrigerant and is discharged from the compressors 16 along with thegaseous refrigerant and recovered by the oil separator 32. The oilrecovered by the oil separator 32 is through an oil returning circuit(not shown) to the sliding parts of the compressors 16.

When determining that the refrigerant is not sufficient and is in shortsupply, the control device of the operating outdoor unit 12B transmits asignal requesting the refrigerant to the control device of the stoppedoutdoor unit 12A. On the other hand, the control device of the stoppedoutdoor unit 12A receiving the refrigerant request signal opens at leastone of the on-off valve 80 on the first refrigerant supply pipe 78, theon-off valve 88 on the second refrigerant supply pipe 84, the on-offvalve 94 on the third refrigerant supply pipe 92, the on-off valve 100on the fourth refrigerant supply pipe 98 and the on-off valve 106 of theoil supply pipe 104 to supply the refrigerant to the operating outdoorunit 12B.

In addition, a refrigerant filling port 112 for filling the refrigerantis provided in the outdoor-unit connecting pipe 70 of the outdoor units12A, 12B. Specifically, the refrigerant filling port 112 is provided ina portion of the outdoor-unit connecting pipe 70 between the connectingpart 70 b connected to the oil supply pipe 104 and the expansion valve110.

For example, after a plurality of the heat pumps 10A, 10B is disposed,or specifically, after a plurality of the outdoor units 12A, 12B and aplurality of the indoor units 14A, 14B are disposed and connected, therefrigerant filling port 112 is used for filling the outdoor units 12A,12B of the respective heat pumps 10A, 10B with the refrigerant.

When each of the outdoor units 12A, 12B is filled with the refrigerantvia the refrigerant filling port 112, an operator closes the manualon-off valve 72 of the outdoor-unit connecting pipe 70. While therespective compressors 16 of the outdoor units 12A, 12B are inoperation, the refrigerant is filled via the refrigerant filling port112. Therefore, the outdoor-unit connecting pipe 70 provided with therefrigerant filling port 112 functions as a path for filling therefrigerant.

Since the manual on-off valve 72 and the refrigerant filling port 112are provided on the outdoor-unit connecting pipe 70, the manual on-offvalve 72 and the refrigerant filling port 112 are close as shown in FIG.2. As a result, the operator can confirm the closed state of the manualon-off valve 72 before filling the refrigerant via the refrigerantfilling port 112 into the outdoor units 12A, 12B.

The refrigerant filled into the outdoor-unit connecting pipe 70 via therefrigerant filling port 112 is atomized by the expansion valve 110 andgasified by the assist-evaporation heat exchanger 54. The gasifiedrefrigerant flows into the compressors 16. The refrigerant is thendischarged by the compressors 16 and filled into the entire path.

As described above, according to the present embodiment, the heat pumps10A, 10B having the outdoor units 12A, 12B and the indoor units 14A, 14Bcan be provided, and the heat pumps 10A, 10B are configured such thatwhen the heat pumps are used as a plurality of heat pumps, therespective outdoor units 12A, 12B of the heat pumps 10A, 10B canexchange the refrigerant with the indoor units 14A, 14B of a pluralityof the heat pumps 10A, 10B, and include the refrigerant filling port112.

Although the present invention has been described with the embodiment,the present invention is not limited thereto.

For example, although the present invention has been described by usingthe two heat pumps 10A, 10B in the embodiment, the present invention isnot limited to two heat pumps. For example, three or more heat pumps maybe included.

In the case of the embodiment, the heat pumps 10A, 10B each have the oneoutdoor unit 12A, 12B and the two indoor units 14A, 14B; however, thepresent invention is not limited thereto. Three of more indoor units maybe included for one outdoor unit of the heat pump.

Additionally, each of the heat pumps 10A, 10B according to theembodiment can be used alone. In this case, the manual on-off valve 72,the on-off valve 80 on the first refrigerant supply pipe 78, the on-offvalve 88 on the second refrigerant supply pipe 84, the on-off valve 94on the third refrigerant supply pipe 92, the on-off valve 100 on thefourth refrigerant supply pipe 98, and the on-off valve 106 of the oilsupply pipe 104 are kept in the closed state.

The heat pump according to the present invention is not limited to theheat pumps 10A, 10B of the embodiment. In a broad sense, the heat pumpaccording to the present invention is a heat pump having an outdoorunit, the outdoor unit including a compressor, an oil separator providedin a discharge path of the compressor, an outdoor-unit connecting pipeconnecting an intake path of the compressor and an outdoor unit of ananother heat pump for supplying a refrigerant to the outdoor unit of theanother heat pump, an oil supply pipe extending from a predeterminedposition of the oil separator and connecting to the outdoor-unitconnecting pipe, an on-off valve provided on the oil supply pipe, anexpansion valve provided in a portion of the outdoor-unit connectingpipe between a connecting part connected to the intake path and aconnecting part connected to the oil supply pipe, and a refrigerantfilling port provided in a portion of the outdoor-unit connecting pipebetween the connecting part connected to the oil supply pipe and theexpansion valve.

In a broad sense, another heat pump according to the present inventionis a heat pump having an outdoor unit, the outdoor unit including acompressor, an oil separator provided in a discharge path of thecompressor, a refrigerant filling pipe connecting an intake path of thecompressor and an outdoor unit of an another heat pump for filling theintake path of the compressor with a refrigerant supplied from theoutdoor unit of the another heat pump, an oil supply pipe extending froma predetermined position of the oil separator and connecting to therefrigerant filling pipe, an on-off valve provided on the oil supplypipe, an expansion valve provided in a portion of the refrigerantfilling pipe between a connecting part connected to the intake path anda connecting part connected to the oil supply pipe, and a refrigerantfilling port provided in a portion of the refrigerant filling pipebetween the connecting part connected to the oil supply pipe and theexpansion valve.

The present invention is applicable to a heat pump having an oilseparator provided in a discharge path of a compressor.

Although the present invention has been sufficiently described in termsof the preferable embodiment with reference to the accompanyingdrawings, various variations and modifications are apparent to thoseskilled in the art. It should be understood that such variations andmodifications are included in the present invention without departingfrom the scope of the present invention according to appended claims.

The disclosures of description, drawings, and claims of Japanese PatentApplication No. 2014-237145 filed on Nov. 21, 2014 are incorporatedherein by reference in their entirety.

EXPLANATIONS OF LETTERS OR NUMERALS

10A heat pump

10B heat pump

12A outdoor unit

12B outdoor unit

16 compressor

32 oil separator

70 outdoor-unit connecting pipe

70 a connecting part

70 b connecting part

104 oil supply pipe

106 on-off valve

110 expansion valve

112 refrigerant filling port

1. A heat pump having an outdoor unit, the outdoor unit including acompressor, an oil separator provided in a discharge path of thecompressor, an outdoor-unit connecting pipe connecting an intake path ofthe compressor and an outdoor unit of an another heat pump for supplyinga refrigerant to the outdoor unit of the another heat pump, an oilsupply pipe extending from a predetermined position of the oil separatorand connecting to the outdoor-unit connecting pipe, an on-off valveprovided on the oil supply pipe, an expansion valve provided in aportion of the outdoor-unit connecting pipe between a connecting partconnected to the intake path and a connecting part connected to the oilsupply pipe, and a refrigerant filling port provided in a portion of theoutdoor-unit connecting pipe between the connecting part connected tothe oil supply pipe and the expansion valve.
 2. A heat pump having anoutdoor unit, the outdoor unit including a compressor, an oil separatorprovided in a discharge path of the compressor, a refrigerant fillingpipe connecting an intake path of the compressor and an outdoor unit ofan another heat pump for filling the intake path of the compressor witha refrigerant supplied from the outdoor unit of the another heat pump,an oil supply pipe extending from a predetermined position of the oilseparator and connecting to the refrigerant filling pipe, an on-offvalve provided on the oil supply pipe, an expansion valve provided in aportion of the refrigerant filling pipe between a connecting partconnected to the intake path and a connecting part connected to the oilsupply pipe, and a refrigerant filling port provided in a portion of therefrigerant filling pipe between the connecting part connected to theoil supply pipe and the expansion valve.